Sponge mop



FIG. 1 is a longitudinal perspective view of a sponge mop embodying my new design shown;

FIG. 2 is a bottom plan view of my new design;

FIG. 3 is a longitudinal side elevational view of my new design;

FIG. 4 is a top plan view of my new design;

The undisclosed sides are the same in appearance as the side shown in FIG. 3. 

The ornamental design for a sponge mop, as shown and described. 